Tuning questions..

[2007 5.9]

I tried logging some stuff yesterday.. Looks like I'm not getting the amount of fuel I should be getting and dropping off too early which is exactly what it feels like. Do I use the logging to see how it's acting and then figure out where to make the changes to fix what it's not doing? I read something about auto correcting stuff somewhere and I don't know if this is even related to any of the logging and tuning on the Cummins. I figured out how to make a "map" and then log it which is how I found out about the fuel dropping off early and not getting enough. I think I need to up my pulse width?

How much mm3 are you commanding/seeing??

Is your drop in fueling happening around 2800rpms??

~Les

[68showngo]

I will have to look at that again, but yes I think so. Max I think was 130 and it dropped to 115 or so by around 3k RPMs. I thought the commanded mm3 was 160, but maybe I just didn't tune something right, and I did go through nearly every table to try to get it to not de-fuel up top, but again I might have done something wrong.

[2007 5.9]

I will have to look at that again, but yes I think so. Max I think was 130 and it dropped to 115 or so by around 3k RPMs. I thought the commanded mm3 was 160, but maybe I just didn't tune something right, and I did go through nearly every table to try to get it to not de-fuel up top, but again I might have done something wrong.

Correct, at 2800rpms, there is a fueling limiter that is still being looked for.

Some trucks command 140mm3 and some more...not sure why.

Log calculated load next time and report your peak number.

I've got two trucks with exact same tune, one only commands 145mm3 and the other will command 200mm3. Again both trucks have the exact same tune...

The 145mm3 truck has a peak load of 73%, while the 200mm3 truck will get to 140%.

~Les

[68showngo]

Which PIDs do I select or how do I get to the calculated load?

[02dodge]

Correct, at 2800rpms, there is a fueling limiter that is still being looked for.

Some trucks command 140mm3 and some more...not sure why.

Log calculated load next time and report your peak number.

I've got two trucks with exact same tune, one only commands 145mm3 and the other will command 200mm3. Again both trucks have the exact same tune...

The 145mm3 truck has a peak load of 73%, while the 200mm3 truck will get to 140%.

~Les

Hey Les Have you looked at D0791? This table is Fuel Pressure Reg., Max duty cycle, RPM Axis. I noticed while playing with a tune that this table stops at 2700rpm. I dont know if this would have anything to do with the fuel being pulled above 2700.

Patrick

[2007 5.9]

Which PIDs do I select or how do I get to the calculated load?

I don't remember at the moment...I think it's in the engine status group.

~Les

[2007 5.9]

Hey Les Have you looked at D0791? This table is Fuel Pressure Reg., Max duty cycle, RPM Axis. I noticed while playing with a tune that this table stops at 2700rpm. I dont know if this would have anything to do with the fuel being pulled above 2700.

Patrick

I have not, I'll look at it tonight when I get to my computer. Good looking out.

~Les

[68showngo]

I upped that to 3500 RPM on this tune I tried where it dropped off at the end. I just upped the pulse width on that tune to try now and see what my fuel looks like. On my next try I will up the max duty cycle to 71, 71, 75, 79, and 83 and see what happens.

[68showngo]

The numbers are mm3 of fuel from my last 3 logs. Can't wait to try and up the max duty cycle and possible monitor my rail pressure, but I gotta get back to work now...

This is stock tune, 1600-3400 RPMs 100% throttle.
121.841030 - 1600
112.567932 - 1800
108.891905 - 2000
132.082200 - 2200
132.758149 - 2400
130.535426 - 2600
137.925967 - 2800
127.064832 - 3000
100.186819 - 3200
79.094202 - 3400

This is my tune from 2000 RPMs to 3200.
120.380432 - 2000
118.993430 - 2200
114.630390 - 2400
108.229968 - 2600
101.300823 - 2800
94.328702 - 3000
86.063663 - 3200

This is my tune with 3% upped pulse width all the way through and another 15% on the top half. This obviously didn't help.. 1400-3400 RPMs
93.123489 - 1400
104.110051 - 1600
115.336275 - 1800
117.711566 - 2000
117.131694 - 2200
114.218565 - 2400
108.343699 - 2600
100.346466 - 2800
93.722258 - 3000
78.548853 - 3200
62.870810 - 3400

[2007 5.9]

Good log....keep us updated with new duty cycle logs.

~Les